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Diffstat (limited to 'inc/glm/detail/type_half.inl')
| -rw-r--r-- | inc/glm/detail/type_half.inl | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/inc/glm/detail/type_half.inl b/inc/glm/detail/type_half.inl new file mode 100644 index 0000000..4632bd4 --- /dev/null +++ b/inc/glm/detail/type_half.inl @@ -0,0 +1,277 @@ +///////////////////////////////////////////////////////////////////////////////////
+/// OpenGL Mathematics (glm.g-truc.net)
+///
+/// Copyright (c) 2005 - 2015 G-Truc Creation (www.g-truc.net)
+///
+/// This half implementation is based on OpenEXR which is Copyright (c) 2002,
+/// Industrial Light & Magic, a division of Lucas Digital Ltd. LLC
+///
+/// Permission is hereby granted, free of charge, to any person obtaining a copy
+/// of this software and associated documentation files (the "Software"), to deal
+/// in the Software without restriction, including without limitation the rights
+/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+/// copies of the Software, and to permit persons to whom the Software is
+/// furnished to do so, subject to the following conditions:
+///
+/// The above copyright notice and this permission notice shall be included in
+/// all copies or substantial portions of the Software.
+///
+/// Restrictions:
+/// By making use of the Software for military purposes, you choose to make
+/// a Bunny unhappy.
+///
+/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+/// THE SOFTWARE.
+///
+/// @ref core
+/// @file glm/detail/type_half.inl
+/// @date 2008-08-17 / 2011-06-15
+/// @author Christophe Riccio
+///////////////////////////////////////////////////////////////////////////////////
+
+namespace glm{
+namespace detail
+{
+ GLM_FUNC_QUALIFIER float overflow()
+ {
+ volatile float f = 1e10;
+
+ for(int i = 0; i < 10; ++i)
+ f *= f; // this will overflow before the for loop terminates
+ return f;
+ }
+
+ union uif32
+ {
+ GLM_FUNC_QUALIFIER uif32() :
+ i(0)
+ {}
+
+ GLM_FUNC_QUALIFIER uif32(float f) :
+ f(f)
+ {}
+
+ GLM_FUNC_QUALIFIER uif32(uint32 i) :
+ i(i)
+ {}
+
+ float f;
+ uint32 i;
+ };
+
+ GLM_FUNC_QUALIFIER float toFloat32(hdata value)
+ {
+ int s = (value >> 15) & 0x00000001;
+ int e = (value >> 10) & 0x0000001f;
+ int m = value & 0x000003ff;
+
+ if(e == 0)
+ {
+ if(m == 0)
+ {
+ //
+ // Plus or minus zero
+ //
+
+ detail::uif32 result;
+ result.i = (unsigned int)(s << 31);
+ return result.f;
+ }
+ else
+ {
+ //
+ // Denormalized number -- renormalize it
+ //
+
+ while(!(m & 0x00000400))
+ {
+ m <<= 1;
+ e -= 1;
+ }
+
+ e += 1;
+ m &= ~0x00000400;
+ }
+ }
+ else if(e == 31)
+ {
+ if(m == 0)
+ {
+ //
+ // Positive or negative infinity
+ //
+
+ uif32 result;
+ result.i = (unsigned int)((s << 31) | 0x7f800000);
+ return result.f;
+ }
+ else
+ {
+ //
+ // Nan -- preserve sign and significand bits
+ //
+
+ uif32 result;
+ result.i = (unsigned int)((s << 31) | 0x7f800000 | (m << 13));
+ return result.f;
+ }
+ }
+
+ //
+ // Normalized number
+ //
+
+ e = e + (127 - 15);
+ m = m << 13;
+
+ //
+ // Assemble s, e and m.
+ //
+
+ uif32 Result;
+ Result.i = (unsigned int)((s << 31) | (e << 23) | m);
+ return Result.f;
+ }
+
+ GLM_FUNC_QUALIFIER hdata toFloat16(float const & f)
+ {
+ uif32 Entry;
+ Entry.f = f;
+ int i = (int)Entry.i;
+
+ //
+ // Our floating point number, f, is represented by the bit
+ // pattern in integer i. Disassemble that bit pattern into
+ // the sign, s, the exponent, e, and the significand, m.
+ // Shift s into the position where it will go in in the
+ // resulting half number.
+ // Adjust e, accounting for the different exponent bias
+ // of float and half (127 versus 15).
+ //
+
+ int s = (i >> 16) & 0x00008000;
+ int e = ((i >> 23) & 0x000000ff) - (127 - 15);
+ int m = i & 0x007fffff;
+
+ //
+ // Now reassemble s, e and m into a half:
+ //
+
+ if(e <= 0)
+ {
+ if(e < -10)
+ {
+ //
+ // E is less than -10. The absolute value of f is
+ // less than half_MIN (f may be a small normalized
+ // float, a denormalized float or a zero).
+ //
+ // We convert f to a half zero.
+ //
+
+ return hdata(s);
+ }
+
+ //
+ // E is between -10 and 0. F is a normalized float,
+ // whose magnitude is less than __half_NRM_MIN.
+ //
+ // We convert f to a denormalized half.
+ //
+
+ m = (m | 0x00800000) >> (1 - e);
+
+ //
+ // Round to nearest, round "0.5" up.
+ //
+ // Rounding may cause the significand to overflow and make
+ // our number normalized. Because of the way a half's bits
+ // are laid out, we don't have to treat this case separately;
+ // the code below will handle it correctly.
+ //
+
+ if(m & 0x00001000)
+ m += 0x00002000;
+
+ //
+ // Assemble the half from s, e (zero) and m.
+ //
+
+ return hdata(s | (m >> 13));
+ }
+ else if(e == 0xff - (127 - 15))
+ {
+ if(m == 0)
+ {
+ //
+ // F is an infinity; convert f to a half
+ // infinity with the same sign as f.
+ //
+
+ return hdata(s | 0x7c00);
+ }
+ else
+ {
+ //
+ // F is a NAN; we produce a half NAN that preserves
+ // the sign bit and the 10 leftmost bits of the
+ // significand of f, with one exception: If the 10
+ // leftmost bits are all zero, the NAN would turn
+ // into an infinity, so we have to set at least one
+ // bit in the significand.
+ //
+
+ m >>= 13;
+
+ return hdata(s | 0x7c00 | m | (m == 0));
+ }
+ }
+ else
+ {
+ //
+ // E is greater than zero. F is a normalized float.
+ // We try to convert f to a normalized half.
+ //
+
+ //
+ // Round to nearest, round "0.5" up
+ //
+
+ if(m & 0x00001000)
+ {
+ m += 0x00002000;
+
+ if(m & 0x00800000)
+ {
+ m = 0; // overflow in significand,
+ e += 1; // adjust exponent
+ }
+ }
+
+ //
+ // Handle exponent overflow
+ //
+
+ if (e > 30)
+ {
+ overflow(); // Cause a hardware floating point overflow;
+
+ return hdata(s | 0x7c00);
+ // if this returns, the half becomes an
+ } // infinity with the same sign as f.
+
+ //
+ // Assemble the half from s, e and m.
+ //
+
+ return hdata(s | (e << 10) | (m >> 13));
+ }
+ }
+
+}//namespace detail
+}//namespace glm
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